A gamemode that would work with the map the server is on? Say if your on a server with a tornado map then you would like the gamemode to have a style related to the map... Like news reporters for warnings. A dark GUI, and a few other things. Though things i personally like is the PERP style how there is a black border around the screen and you can run out of breath. Realistic gamemodes are cool!

GAMEmodes. I want more gamemodes that feels like fun games, less slow paced roleplaying and gritty shooters. I want more fast casual gamemodes where you compete against other players, preferably without them being simple Deathmatch type games.

I was working on Onslaught:Evolved for the beta, but I got stumped when the items stopped being sent to the client. No idea why it happens, it's included and AddCS'd in the init.lua, and included again in the cl_init.lua.

Advancing teamwork is not really hard. Just make a new snpc for that, and make that npc can kick some asses easily and set high shared bounty(or item dice for participant) then people will stick together and try to kill that snpc.

I made a gun shooting 150hp npc scanner and it was so l33t.
Also it was too hard to kill as fuck and some people quit my game.

Games that encourage players to work together, and punishes people who lone wolf.

Some degree of team-wide strategy is always nice, but no so much that you basically need a super-tightly-knit group of players working together to accomplish their goals - I should be able to drop into a random server, into a random team, and still be able to operate fairly well.

The goals and controls of the game should be fairly straightforward, not too dumbed down, and not too complex. If I can't understand at least the basics of the game within five minutes of playing, I'll probably get a bit frustrated with the game.

Gameplay mechanics beyond simple "Go to X, kill Y, defend Z, and buy W" are important, too. You can have those elements, but don't make them the entirety of the game, unless you put some interesting and nonconventional spin on it.